1. Field of the Invention
The present invention relates to optical systems, and more particularly to a lens system for plural wavelength light including a first lens group for exposure and/or ablation use and a second lens group for through-the-lens alignment use.
2. Description of the Prior Art
U.S. Pat. No. 2,550,685, issued May 1, 1951 to S. E. Garutso, entitled OPTICAL OBJECTIVE BALANCE ASSEMBLY, discloses the addition of specially constructed lens elements to known objective lenses or by lens assemblies of entirely new composition. The lenses, with a wide open diaphragm, will give sharp images simultaneously of objects from forty inches on to optical infinity and the horizon. This is accomplished without creating double images, distortion or fuzziness and with a marked three-dimensional effect much more striking than heretofore observed in one-lens pictures.
U.S. Pat. No. 2,591,535, issued Apr. 1, 1952 to S. E. Garutso, entitled BALANCED OPTICAL OBJECTIVE AND FOCUSSING LENS ASSEMBLY, discloses lenses for use in cameras or wherever depth of focus and fidelity of image are important, and its object is to improve these qualities in lenses used for such purposes. A plurality of annular lenses having non-parallel, spherical optical surfaces are coaxially positioned in front of a conventional objective and at least one of the annular lenses has an external diameter equal to that of the conventional objective and at least one other of the annular lenses has an external diameter greater than the internal diameter of the first annular lens and less than the diameter of the conventional objective and the second annular lens having an internal diameter less than that of the first annular lens.
U.S. Pat. No. 2,651,237, issued Sep. 8, 1953 to S. E. Garutso, entitled BALANCED FOCUS LENS SYSTEM, relates to lenses such as the objectives of cameras and other optical instruments where a correct image of objects or scenes is desired, and its object is to increase the depth of focus, improve the fidelity of the image and decrease distortion by combining with a known type of lens, one or more annular converging lens elements called balancing elements and which overlie the peripheral part of the elements of the conventional lens.
With full diaphragm opening, any required depth of focus within wide limits depending upon the character of the conventional lens used, can be attained by combining with it annular balancing lens elements each having the central opening or non-refractive area such that its effective diameter is in the region of 2/3 of the diameter of the cone of rays transmitted by the conventional lens, measuring at the point where the balancing element is located.
The three Garutso patents are directed to lens systems for photography for viewing at different distances with the same wavelength. The present invention is a lens system for different wavelengths at the same distance.
U.S. Pat. No. 4,256,370 issued Mar. 17, 1981 to Gold, entitled CORED LENS FOR LARGE REFRACTING TELESCOPES describes a refracting telescope which is comprised essentially of an objective lens and an eyepiece is provided with a cored or annular lens for the objective lens thereby increasing the resolving power of the telescope without adversely affecting the light gathering capabilities of the telescope.
U.S. Pat. No. 4,626,079 issued Dec. 2, 1986 to Nakamura et al, entitled DARK FIELD ILLUMINATION APPARATUS FOR EPI-ILLUMINATION SYSTEM describes a dark field illumination apparatus for epi-illumination system, an annular light beam which is coaxial with the optical axis of the objective lens and is supplied along an optical path formed surrounding the objective lens. An annular condenser member is arranged near the object side end of the objective lens in such manner that the beam reaches the objective surface while being concentrated in the direction toward the optical axis by the condenser member.
U.S. Pat. No. 4,376,889 issued Mar. 15, 1983 to Swift, entitled LOW LIGHT LEVEL VISION APPARATUS, relates to low light level or night vision apparatus, and particularly goggles having an objective lens to focus incident light on to an image intensifier and a magnifier enabling an observer to view a magnified version of the intensified image includes a wavelength selective filter with a hole or aperture through which light of other wavelenhths can pass, the wavelength selective filter or means associated with the hole or aperature being arranged to have a focussing effect so that light from a distant scene or object of a wavelength passed by the filter can be properly focussed on the image intensifier, and light from a near scene or object passing through the hole or aperture can simultaneously also be properly focussed on the image intensifier, so that either or both images can be viewed in a focussed condition without adjustment of the apparatus.
United Kingdom Patent 258,755 issued Sep. 30, 1926 to Parodi, entitled IMPROVEMENTS IN AND RELATING TO PERISCOPES, describes an improved periscope with two toric lenses equal and symmetrically arranged each at one end of a vertical optical fixed tube with converging lenses arranged between the two toric lenses.
The Gold patent relates to annular lenses only for purposes of resolution and weight reduction. The Nakamura patent relates to annular lenses used for illuminations, not alignment. The Swift patent is for night vision at different distances and the Parodi patent relates to panoramic viewing.